Anchor for adjacent slabs of concrete pavements



March 11, 1952 1.. G. BLACKHALL 2,588,609

ANCHOR FOR ADJACENT SLABS OF CONCRETE PAVEMENTS Filed May 15, 1947 INVENTOR. 400/5 6 fi/ack/wfl BY Patented Mar. 11, 1952 UNITED STATES PATENT OFFICE ANCHOR FOR ADJACENT SLABS OF CONCRETE PAVEMENTS Louis G. Blackhall, Albany, N. Y;

Application May 13, 1947, Serial No. 747,635 2 Claims. (01.94-8

anchor of this type which is adapted to prevent a lateral separation of adjacent slabs of concrete as well as differential heaving thereof, and also to an anchor which is adapted, to prevent differential heaving of two adjacent slabs of concrete while permitting lateral separation thereof due to contraction as a result of low temperatures.

Substantially all concrete pavements are constructed with longitudinally-spaced, transverse joints, commonly referred to as expansion joints but which, for the most part, function as contraction joints; and, where the pavement is of I member may be readily inserted, after the resubstantial width it is usually laid in two or more longitudinally-extending strips so that longitudinally-extending joints exist between said strips. In the latter case, such strips frequently become rather widely separated, unless anchored together, due either to subgrade failures or, to the penetration of water into the joint between the strips which, when it freezes, forces the strips apart. Where the temperatures vary frequently from above freezing to below freezing, the lateral separation of the strips of concrete becomes progressively greater from day to day where the conditions are such that water penetrates the space between the adjacent strips and alternately freezes and'thaws. This, of course, is due to the fact that water, in freezing," expands as ice, and exerts a substantial force on anything which opposes the expansion. Sometimes, due to subgrade conditions, when the slabs or strips are not anchored together, one slab may be forced upwardly to a distance substantially above the adjacent slab so that, in the case of a transverse joint, at transverse bump or, where two or more strips of concrete run lengthwise of the road, a longitudinally-extending difierential in elevation may. be produced at the joint between the slabs or strips. 7 V 7 g One of the objectsof my invention is to provide an anchor for preventing difierential heaving of two adjacent slabs or strips of concrete pavement. Another object is to provide an anchor which, in addition to preventing difierential. heaving, will also prevent lateral separation of two longitudinally-extending slabs or stripsof concrete. Another object is to produce an anchoring device of the character described above comprising two members of which one of said members maybe embedded in the concrete. of the first laid slab and into which the second moval of the side form from the first laid slab, so that the two anchor members are assembled in axial alignment and wedging engagement with each other. Another object is to provide an anchoring device of such character that the second member, when inserted in wedging engagement with the first member, will be supported thereby so that the concrete in the next laid slab. may. be poured around it withoutdanger of displac ing it.

I accomplish these objects by. means of th novel elements and the combinations and are:

rangements thereof described below and illuS:

trated in the accompanying'drawing in which,;

Fig. 1 is a plan view of. one of the members of my anchor; Fig. 2 isan end view of the member shown in Fig. 1;

Fig. 3.is a side elevation view of the member shown in Figs. 1 and 2; i

Fig. 4 is a plan View of the other member of my anchor; I Fig. 5 is a right hand end view of the member shown in Fig. 4; i

Fig.6 is a section of Fig. 4 in theplane 66;

Fig. 7 is a section of Fig. 5 in the plane 1-1; Fig. 8 is. a fragmentary, transverse section of one longitudinally-extending strip of concrete pavement showing a fragmentary portion of one of the members of my anchor embedded therein and illustrating how the member is secured to the side form prior to and during the pouring and setting of the concrete;

Fig. 9 is a section of Fig. 8 in the plane 9-9; and

Figs. 1 to 10 inclusive:

One member of my anchor, as shown in Figs. 1;-2 and-3, comprises a bar I having cross members 2 and 3, respectively, at each end. The extremities of the cross members 2 and 3 are preferably cast to a radius 4 approximating, but

slightly less than, the inside radius of the socket on the other member which will be described below.

The other member, as shown in Figs. 4, 5. 6 and 7, comprises a bar 5 having a crossmember 6 .at one end thereof which is substantially identi- "cal with the cross members 2 and 3 of the mem- Fig. 10 is a sectional view similar to Fig 8 her described above. At the other end, the member shown in Figs. 4, 5, 6 and 7 is provided with a hollow, cylindrical head I forming a socket 8 to which entrance is provided through the slotted opening 9 in the end thereof. The opening 9 is of such size as to pass either of the cross members 2 or 3 on the first described member. In the bottom thereof, the socket is provided with a pair of diametrically and symmetricallydisposed, arcuate ramps I and II which are spaced apart sufficiently to permit either of the cross members 2 or 3 to be positioned therebetween when in the socket 8. The distance between the bottom I2 (see Fig. 7) of the socket 8 and the inner surface I3 of the top or front of the socket is only slightly greater than the width I3 of the cross members 2 and 3, but the distance between the tops I4 and I5 of the ramps and the inner surface I3 of the front of the socket is less than the width I3 of the members 2 and 3. Thus, by inserting either the member 2 or the member 3 in the socket 8 through the opening 9 and effecting relative rotation of the two members of the anchor, the cross member 2 or 3 which is inserted in the socket will be wedged between the ramps and the inner surface I3 of the front of the socket.

In Figs. 8 and 10, I have shown how my device is used. The side form I8 for the slab I! is provided at spaced intervals with holes I8. Short bolts or studs I9 having a cross member 20 on one end thereof, similar to the cross members 2 and 3 shown in Figs. 1, 2 and 3, are passed through the holes I8 in the form I6 and the nuts 2I are applied thereto to hold the bolts in place, but not tightened. The cross members 20 are then inserted in the sockets 8 on the anchor members of the type shown in Figs. 4-7, inclusive. The ends 22 of the studs or bolts I9 are squared, as shown in Fig. 9, and, by placing a wrench on the squared portion of the stud I9 and a second wrench on the bar 5, associated therewith, or the cross member 6 thereon, as shown in Fig. 4, relative rotation of the anchor member and the associated stud or bolt I9 will cause the cross member on the stud or bolt to ride up on the ramps I0 and II and thus wedge the anchor member and the bolt together, whereupon the nut 2I may be tightened.

After the concrete forming the slab IT has been poured and set so that the form I6 can be removed, the nut 2I is loosened, and the form IS can then be pulled away from the side of the slab ll. The bolt or stud I9 can be removed by applying a wrench to the squared portion 22 thereof and turning it until the cross member 20 is in line with the slot 9 in the socket of the anchor member whereupon the bolt may be pulled out. It will be apparent that the slot 9 in the anchor member embedded in the slab I'I will thus be exposed on the side of the slab I! which will be adjacent the next laid slab. The second anchor member, such as shown in Figs. 1, 2 and 3, is then passed through the slotted opening in the anchor member embedded in the 4 slab I1 and turned with a wrench until the anchor members are in firm wedging engagement and in axial alignment with each other, as shown in Fig. 10. The concrete forming the second slabmay then be oured about the anchor member which projects from the slab I'I without danger of displacing it. When the concrete in the second laid slab is set, it will be apparent that the slabs will be locked together so that there can be no differential heaving and no lateral separation thereof.

The members of my anchor may be cast, but are preferably formed of malleable iron which is somewhat ductile and less liable to fracture under stress than ordinary gray cast iron.

What I claim is:

1. An anchor for preventing differential heaving and lateral separation of two adjacent slabs of a concrete pavement; said anchor comprising a first, elongated, metal bar adapted to be embedded in the first laid slab, and a second, elonggated, metal bar adapted to be embedded in the second laid slab; said first bar having a cylindrical socket in one end provided with an entrance to said socket in the end of said bar adapted to be exposed in that end of said first laid slab adjacent the other of said slabs when laid, and having circumferentially-spaced portions of said bar extending inwardly partially across said entrance; said second bar having laterally projecting portions at one end thereof disposed in said socket and of a size and shape adapting them to be withdrawn from said socket when positioned between said inwardly extending portions of said first bar; and ramps in the bottom of said socket wedgingly cooperating with the portions of said second bar within said socket upon relative rotation of said bars and holding said portions of said second bar within said socket in contact with said inwardly extending portions of said first bar and said bars in axial alignment; whereby, after said first slab is laid with said first bar embedded therein, said second bar may be rigidly connected to said first bar, and the concrete forming said second slab then poured about 2. The structure set forth in claim 1 in which each of said bars is provided with a laterally ofiset portion positioned to be embedded in the concrete in which the bar is embedded to anchor said bar therein.

LOUIS G. BLACKHALL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 9,122 Sergeant July 13, 1852 1,588,628 Sellers June 15, 1926 1,762,572 Davidson June 30, 1930 1,933,536 Awbrey Nov. 7, 1933 2,014,826 Wildrick Sept. 17, 1935 2,127,973 Isett Aug. 23, 1938 

